Abstract

For reusable and expendable launch vehicles as well as for other spacecraft structural
vibration loads are safety critical design drivers impacting mass and lifetime. Here, the
improvement of reliability and safety, the reduction of mass, the extension of service life, as well
as the reduction of cost for manufacturing are desired. Spacecraft structural design in general is a
compromise between lightweight design and robustness with regard to dynamic loads. The
structural stresses and strains due to displacements caused by dynamic loads can be reduced by
mechanical damping based on passive or active measures. Passive damping systems can be
relatively simple and yet are capable of suppressing a wide range of mechanical vibrations.
Concepts are low priced in development, manufacturing and application as well as maintenancefree.
Compared to active damping measures passive elements do not require electronics, control
algorithms, power, actuators, sensors as well as complex maintenance. Moreover, a reliable
application of active dampers for higher temperatures and short response times (e. g. re-entry
environment) is questionable. The physical effect of passive dampers is based on the dissipation of
load induced energy. Recent activities performed by OHB have shown the function of a passive
friction-damping device for a vertical tail model of the German X-vehicle PHÖNIX but also for
general sandwich structures. The present paper shows brand new results from a corresponding
ESA-funded activity where passive damping elements are placed between the face sheets of large
spacecraft relevant composite sandwich panels to demonstrate dynamic load reduction in vibration
experiments on a shaker. Several passive damping measures are investigated and compared.